SEES 2022: Effect of Container Surface Area on Mosquito Oviposition

After reading the article "Container Type Affects Mosquito Oviposition Choice," I was inspired to test how a container's surface area, an abiotic parameter, may affect female mosquito oviposition choice (Parker et al). At first, I was really curious about how the ratio of surface area to volume in a container affected oviposition choice. Thus, I began my experiment by finding containers with different surface areas but of similar volumes so I could control the volume of water in each container and more effectively isolate whether surface area affected oviposition choice. The first containers I used looked like this: 

Then, I checked my traps three days later and found the traps entirely dried out. I wasn't sure what to do, because I had controlled so many variables such as their color, material type, volume of water, and amount of grass/rocks I put in the water, but I knew I had to change something or my traps would keep drying out. I tried filling the containers with as much water as they could hold, so at least all the aforementioned variables would be controlled except for volume of water. However, when I checked the tarps five days later they were all dried out except for one container. That trap had tons of mosquito larvae and some eggs, which was really cool. I looked at them under a microscope and took many photos, such as these:

Since the containers' water, even when the containers were completely filled, wasn't lasting longer than a few days I decided to change the containers to be much much bigger. I went out and bought and set up larger containers that would take much longer to dry out. I filled them with water and put grass, rocks, and leaves in the water and hid them to make sure they would shaded and concealed enough, despite their size, to not be frequently tampered with. Now, my experiment looks like this: 

I will be checking in on them in 2 days to see my results, I expect they will be filled with mosquito eggs and larvae! 

Update 1: I unfortunately have one remaining trap location because my traps from one location have been seemingly stolen. So... I still have two large containers with unique surface areas remaining at an AOI, which I will continue to compare to determine whether the container with more surface area is more or less appealing for female mosquito oviposition at that AOI. 

Updated results

June 28 

In bucket with 44.28 in^2 of surface area - nothing

In container with 166.75 in^2 of surface area - 3 culex egg rafts, 2 culex larvae

July 4

In bucket with 44.28 in^2 of surface area - 2 culex pupae emerging into adults

In container with 166.75 in^2 of surface area - 82 culex egg rafts, 4 culex pupae emerging into adults, 5 anopheles larvae, 9 culex larvae, and 4 aedes larvae. 

image of culex (I think?) pupa emerging into an adult-

Update 2: On my fourth week of data I found a huge haul of mosquitoes in my large container! The container with 166.75 in^2 of surface area held over 1303 mosquito larvae! Because the entire container was full of mosquitoes (look at this image), I couldn't count all of them! I spent about 20 minutes scooping larvae from the top and waiting for them to reemerge for oxygen until I decided it'd be nearly impossible to capture them all without having to carry the entire container back home (that was never a possibility).

Then, I took as many as I could easily carry back and dumped the remaining contents of the container to make sure the mosquitoes would die before maturing into adults. Here are the mosquitoes I took back and counted to a total of 1303 larvae:

To check their species and life stage, I scooped out small quantities of water at a time using one of my smaller containers that I stopped using because they were too small and dried up quickly (see first blog post). Then, I slowly poured out the water I had scooped onto a plate so I could see the amount, species, and stage of the mosquitoes. I counted 1293 Culex larvae, and there were 10 mosquito larvae that I couldn't identify that were larger than the Culex larvae. I think one major reason why I trapped so many this week is because the water was super smelly after being stagnant and outside with grass in its water for weeks. It was smelly last week too, but I think it became even more smelly, making it more attractive to mosquito oviposition. There were also countless amounts of really small larvae that (I think?) were mosquitoes but they were so small and abundant that I couldn't count them. 

In my bucket with 44.28 in^2 of surface area, I found 5 anopheles larvae and 2 culex larvae.

I unfortunately didn't take more photos of the culex larvae because I could easily identify them by their long siphon, but I took a few photos of larvae I wasn't sure how to identify, such as these: